Flexible corner flashing

ABSTRACT

Embodiments of the present invention relate to the field of construction, and more particularly to waterproofing the exterior of buildings. Specific embodiments of the invention provide devices for preventing moisture leakage between a roof and chimney, where the roof and chimney intersect and at the corners of the chimney. The present invention in particular provides flashing comprising: an L-shaped planar member having an interior L-shaped edge; and two flanges connected with a web and integral with the L-shaped member, disposed along the interior L-shaped edge, and having a continuous upper edge; wherein the interior edge of the L-shaped member is shorter in length than the continuous upper edge of the flanges.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to the field of construction, and more particularly to waterproofing the exterior of buildings. Specific embodiments of the invention provide devices for preventing moisture leakage between a roof and chimney, where the roof and chimney intersect and at the corners of the chimney.

2. Description of Related Art

Waterproofing of portions of exterior buildings, especially above the roof line, typically involves custom fitting of “flashing” around the surfaces to be waterproofed. Such custom fitting often requires skill and valuable labor time in measuring, cutting, fitting, securing, and sealing the flashing in place to ensure a waterproof seal. Metal, such as copper, aluminum, or steel, is a preferred material, especially for chimneys or other surfaces that may tend to transfer heat to the flashing during use. Plastic and rubber can also be used but building code limitations may prevent their use in certain applications. When using metal flashing, a sealant is required between the flashing and the surface to which it is applied, or along the edge of the flashing, to prevent moisture from entering the space between the surfaces. This is because metal, although deformable, tends to retain its shape once deformed due to its lack of resiliency. Resilient plastics and rubbers, however, can be molded around a surface to obtain a desired waterproof fit without the need of additional sealants.

The corners of building structures that project from another surface, such as the corners of a chimney on a roof, are particularly difficult to waterproof. This is because most flashing materials are planar sheets of material and must be cut to an appropriate size, bent in one direction to lie along the surface of the chimney and the surface of the roof, then bent in another direction to wrap around the corner of the chimney. Further cutting is usually required for planar sheets of material because they do not have the capability of stretching to accommodate both types of bending. When cut to fit around the corner of a chimney, however, the flashing usually does not cover the desired area completely and additional flashing material is usually needed to cover these exposed surfaces. In this manner, multiple seams are then created between the flashing material and the supplemental flashing material, in addition to seam between the flashing material and the roof Each of these seems must then be sealed (or soldered) adequately to fully waterproof the site.

Existing products have attempted to address some of these issues. For example, U.S. Pat. No. 5,414,964, entitled “Flashing for Buildings,” and incorporated by reference herein in its entirety, describes a flashing product comprising the combination of a resilient material (rubber) and a non-resilient material (metal) bonded together. The metal portion can be stretched in a longitudinal direction, e.g., along a roof surface, and maintain itself and the rubber to which it is bonded in the stretched position, while the rubber portion provides a seal around a protrusion from the roof, such as a chimney, by deforming to accommodate the chimney then rebounding around the surface of the chimney To accommodate a different sized chimney or protrusion, however, the flashing must be cut to the appropriate size protrusion, requiring skill and added labor costs. Because the metal and rubber portions of the flashing are bonded together, there is opportunity for failure of the device at this location.

Another type of existing flashing used for arched windows is similarly deficient. U.S. Pat. No. 6,981,348, entitled “Flashing for an Exterior Arched Surface and Method,” which is hereby incorporated by reference herein in its entirety, describes another type of flashing for arched windows comprising steel and rubber. The L-shaped metal base (which forms two flanges) has flexible flashing material adhesively bonded to its back surface and a portion of its front surface. The metal part of the flanges comprises V-shaped cutouts to allow for the metal flanges to be bent along an arched window frame. The metal base holds the flashing material against the window frame and adjacent wall, while the flashing material provides for a seal along those surfaces. Such flashing, however, would not meet the bending requirements of flashing for chimneys, which need a 90° bend along the length of the flashing to wrap around the chimney (x-z type bending) as well as the ability to bend less than 90° between the chimney and the roof (y-x type bending). Thus, to accommodate the corners of a chimney, this flashing would need to be cut much like a planar sheet of material, which leads to the drawback of requiring additional waterproofing at additional seams.

Further, U.S. Pat. No. 6,715,237, entitled “Flashing Assembly,” and incorporated by reference herein in its entirety, describes a generally L-shaped flashing bent at a 90° angle between flanges, which is integral with or connected to a corrugated end portion at each end of the flashing. Each corrugated end can be deformed around the corner of a chimney and the flanges can be bent to an angle that conforms to the slope between the chimney and the roof The flashing, however, is metal and does not provide the same resiliency that rubber would provide. Additionally, because the flashing is corrugated, the material will not lie flush with the surface of the chimney or roof, allowing for the opportunity for moisture to seep into the seam. Further manipulation of the material, such as hammering out the corrugation and/or adding additional sealant is required for waterproofing.

U.S. Pat. No. 5,077,943, entitled “Corner Flashing,” which is incorporated by reference herein in its entirety, describes a bendable molded polypropylene flashing that can accommodate different inclinations between chimneys and roofs, which is adapted to be lapped or folded to form a tuck causing the surfaces of the flashing to tightly embrace the corner of the chimney. This requires skill to deform the flashing in an acceptable manner at the desired portion of the flashing, while ensuring proper placement of the remaining portion of the flashing, since the material is of a single thickness and type of material.

Other existing products, including the Amerimax Home Prod. 68720 CornerFlex Corner Flashing, comprise planar strips of corrugated metal bent in an L-shape, which are flexible enough to wrap around the corner of a surface. The corrugations in the material in combination with the metal material itself do not provide for an acceptable seal around those surfaces. The corrugations prevent surface-to-surface contact between the flashing and the support to which it is applied along the entire surface of the flashing. Thus, manipulation of the material, for example, hammering the material flat, would be needed. Even then, the metal material lacks resilience to ensure a tight fit with the surface to which it is applied.

It is thus apparent that existing devices and flashing systems have not solved the issue of providing an adequate waterproofing material that is easy to install, can be adapted to and is customizable for various construction situations, and which requires relatively little labor time to install.

SUMMARY OF THE INVENTION

To this end, embodiments of the present invention provide flashing for corners of a chimney or other structure that combines waterproof protection with ease of use and can be adaptable to various construction situations.

Specific embodiments of the invention provide flashing comprising an L-shaped member and two flanges integral with and each disposed along an interior edge of the L-shaped member, wherein the flanges are integral with one another by way of a web and are capable of being rotated from 0-360° relative to the L-shaped member.

In some embodiments, the flanges can be rotated from about 45-315° relative to the L-shaped member. The larger the web, the greater the rotation is possible.

In preferred embodiments, the flashing can comprise a single type of material, such as rubber or plastic, and can be of a thickness that allows for the 0-360° rotation of the flanges relative to the L-shaped member. For example, the transition between each flange and the L-shaped member can be slightly thinner than the remaining material so that the flanges can be folded throughout the full degree of rotation. In embodiments, the web portion connecting the flanges can also be thinner than the flanges themselves, or can comprise a different material or a different composition of the same material to render the web more flexible and/or resilient than the flanges themselves.

The webbing between the flanges can be the same material or a different material than the flanges. In preferred embodiments, the flanges are integral with the web and each other. What is meant by “integral” according to this specification is that the flanges and web, and the flanges and the L-shaped member, appear to be a unitary piece of material. If different materials are used, the materials are preferably fused together to provide for connection of the parts of the flashing in a manner that is not releasable.

Flashing according to embodiments of the invention can be comprised of plastic or rubber material that is flexible and resilient, and may include polypropylene plastic or EDPM rubber as a preferred material.

The material can have a thickness ranging from about 0.1 to 10 mm, or from about 1 to 8 mm, or from about 2 to 5 mm, with the range of about 1 to 3 mm preferred. The flashing can comprise different thicknesses for different portions of the flashing, or can comprise a uniform thickness throughout.

The L-shaped member is preferably about 12 inches by 5 inches and the flanges slightly smaller in surface area. The web material joining the flanges is typically about ½ the length of a flange or a leg of the L-shaped member. Typically, the larger the web, the larger the degree of rotation of the flanges is possible.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate certain aspects of some of the embodiments of the present invention, and should not be used to limit the invention. Together with the written description the drawings serve to explain certain principles of the invention.

FIG. 1 is a schematic illustration showing a representative flashing according to embodiments of the invention.

FIG. 2 is a schematic diagram of another flashing according to the invention.

FIG. 3 is a schematic diagram of a similar flashing to that of the flashing of FIG. 2, approximately as it would appear when removed from the mold.

FIG. 4 is a schematic diagram of a corner flashing embodiment of the invention installed on the corners of a chimney.

FIG. 5 is a schematic diagram of a corner flashing embodiment of the invention installed on the corners of a dormer.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

Reference will now be made in detail to various exemplary embodiments of the invention. It is to be understood that the following discussion of exemplary embodiments is not intended as a limitation on the invention. Rather, the following discussion is provided to give the reader a more detailed understanding of certain aspects and features of the invention.

Particular embodiments may comprise an L-shaped planar member having an interior L-shaped edge; and two flanges connected with a web and integral with the L-shaped member, disposed along the interior L-shaped edge, and having a continuous upper edge; wherein the interior edge of the L-shaped member is shorter in length than the continuous upper edge of the flanges. Such flashing can be configured such that the L-shaped member and the flanges together comprise a single sheet of plastic or rubber material. Preferably, the flashing material is a thermoplastic polypropylene or EDPM rubber. The flashing typically comprises one type of material, but may comprise more than one type of material or different compositions of the same type of material as explained further below.

As shown in FIG. 1, flashing 10 according to embodiments of the invention can comprise a single sheet of plastic or rubber. The sheet can be configured as a generally L-shaped planar member 11 having two rotatable flanges 12 connected by a web 13.

The flashing of FIG. 1 provides flanges 12 disposed at about a 60° angle relative to the L-shaped planar member, as indicated by angle D. Although the flanges can be flexed or folded toward or away from the L-shaped members with minimal effort and without significant stretching of the sheet material, at rest the flanges are separated from the L-shaped material by about 60° in this embodiment. If desired, the flanges 12 can be provided at an angle of about 90° relative to the L-shaped member 11, by using less material for web 13. Likewise, if more material is used (as shown in FIG. 2) for web 13, the flanges 12 can be disposed at a distance closer to the L-shaped member 11, such as 0°, 15°, or 30°.

In embodiments, the flashing can comprise a material that has a thickness that is thinner where the flanges connect with the L-shaped member to allow for greater flexibility of the flanges without stressing the L-shaped member.

Web 13 according to this specification is the portion of material between flanges 12 that is needed to join flanges 12 in order to accommodate flexing of the flanges 12 between 0-90° and between 270-360° relative to the L-shaped member. As illustrated in FIG. 1, the web 13 can be an extension of flanges 12. In such embodiments, flanges 12 are joined together by additional plastic or rubber material to form a web between the flanges.

Flashing embodiments may comprise a web provides for flexing of the flanges to any angular position between 0-360° relative to the L-shaped member without imposing stress on the L-shaped member.

Particular flashing embodiments according to the invention may include a web that provides for flexing of the flanges to any angular position between 45-315° relative to the L-shaped member without imposing stress on the L-shaped member. Some flashings may include a web that provides for flexing of the flanges to an angular position between 0-90° relative to the L-shaped member.

With respect to the composition of the material for the L-shaped member, the flanges, and web, in embodiments the flashing comprises two types of material, wherein the web is a different material or a different composition of the same material as the L-shaped member and flanges. Alternatively or in addition, the material of the flashing at the web can be more flexible and/or resilient than the material of the flashing at the flanges. Even further, the web can be thinner than the flanges.

In embodiments, the flanges 12 are capable of being positioned at right angles to the L-shaped planar member. Each flange is also capable of being positioned in a plane substantially parallel to the L-shaped member, i.e., 0° relative to L-shaped member 11. Movement of the flanges is possible due to folding of the sheet of material along a desired line and the flexibility of the material itself In preferred embodiments, a flange can be rotated from 0-360° relative to a plane in which the L-shaped member lies. Further preferred embodiments provide for rotation of the flange 12 between about 30-330° relative to the L shaped member. As shown in FIG. 1, the flange is positioned at about 60° relative to the planar L-shaped member, but can be rotated less or more if the material is flexed along the fold line or joint between flange 12 and L-shaped member 11.

The ability of the flange to be positioned at various angles provides for a custom fitting of the flashing in unlimited types of construction situations. When installing flashing at the intersection of a chimney and roof for example, typically the surface of one flange of the flashing 10 is first held in place against the surface of the chimney, with the folded edge of the flange in the joint between the chimney and roof Then the surface of the first leg of the L-shaped member (adjacent to that flange and along that fold) is held in place against the surface of the roof. These members are then temporarily or permanently adhered to the chimney and roof surfaces. Once one side of the flashing is secure, the second side of the flashing is wrapped around the corner of the chimney and the fold between the second flange and corresponding portion of the L-shaped member is placed in the joint between that side of the chimney and the roof. Then the planar surface of the second leg of the L-shaped member can be laid on the surface of the roof, followed by similar placement of the second flange along the adjacent side of the chimney. Because the flashing material is sufficiently flexible, the flanges and L-shaped members are effortlessly positioned and with little to no stress on the flashing 10 itself To wrap the corner of the chimney, the web 13 between the flanges of the flashing is folded in an appropriate manner to abut the corner of the chimney and one or more sides of the chimney to provide for a waterproof seal.

In practice, flashing 10 can be used in multiple construction situations. For example, when attaching flashing between a chimney and roof where the roof and chimney meet at a 135° angle, the same angle between one of the flanges and the L-shaped member can be achieved simply by rotating that flange to the desired positioned. On the other side of the chimney, along the same roof line, the roof and chimney would meet at a 45° angle and the same configuration of flashing could be used to accommodate these different angular requirements. According to embodiments of the invention, the same flashing configuration can be used to accommodate the corner joint between two surfaces (e.g., chimney and roof) which meet in any angular situation ranging from 0-360°.

The flashing 10 can comprise any type of plastic or rubber, so long as the material has sufficient flexibility, resiliency, and elasticity to accommodate flexing of the flanges 12 to any angular position from 0-360° relative to the L-shaped member. Specific types of materials that can be used include any plastic or rubber composition and preferably materials that can tolerate high heat or harsh weather conditions without failing, such as thermoplastic EPDM (ethylene propylene diene terpolymer), which provides for maximum resistance to weathering due to ozone and UV light.

The flashing can be any thickness, but is preferably about 45 mil (0.04″ or 1.14 mm), 60 mil (0.06″ or 1.52 mm), 80 mil (0.08″ or 2.0 mm), 100 mil, or 115 mil. Indeed, the flashing can range in thickness from 1-10 mm The thickness of the flashing, or portions thereof, will depend on the particular application for which the flashing is used and will depend on the particular material chosen for the flashing. Thickness of the flashing may also vary throughout the sheet of material by about 0.2 mm due to manufacturing tolerances. The thickness of the flashing may also, or alternatively, vary at portions of the sheet to allow for certain portions of the sheet (such as the flanges) to be more rigid, i.e., have a greater thickness, while other portions of the sheet (such as the webbing connecting the flanges) can be less rigid, i.e., thinner material for the webbing.

Preferred materials for the sheet of flashing are those with a tensile strength (ASTM D 412) of at least 1300 psi, such as about 1650 psi; and/or an elongation to break (ASTM D 412) of at least about 300%, such as 480%; and/or a minimum tear strength (ASTM D 624—Die C) of about 150 lb/in, such as 200 lb/in, such as for uncured EPDM rubber. For cured EPDM rubber flashing, a minimum tensile strength (ASTM D 412—Die C) of 1305 psi is desired; and/or a minimum elongation to break of about 300%; and/or a minimum tear resistance of 150 lbs/in (D—624 Die C) is desired.

Neoprene (cured or uncured) can also be used for the flashing material. For uncured flashing and before vulcanization preferred Neoprene flashings have a modulus, 100%, about 25-75 psi (ASTM D 412—Die C); and/or an ultimate elongation (ASTM D 412—Die C) of at least 400%. After vulcanization, Neoprene type flashings can have a tensile strength (ASTM D 412—Die C) of about 1484 PSI; and/or an elongation of about 267%; and/or a tear resistance (ASTM D412—Die C) of about 171 lbs/in., or higher.

Another material suitable for the flashing according to embodiments of the invention includes thermoplastic olefin (TPO). Such material can have an elongation (ASTM D 412) of about 500%; and/or a tearing strength (ASTM D 751) of at least 55 lpf (245 N), such as 156 lpf (694 N), or 120 lpf (530 N); and/or a water absorption of less than about 8%, such as 4%, or 2%, or 0.1%.

Other materials that can be used include ethylene vinyl acetate and PVC terpolymer thermoplastic, or polypropylene, such as APP (Atactic Polypropylene).

Other characteristics of the material for the flashings can include that the flashing is capable of servicing situations exposed to temperatures ranging from −60 F to +270 F. Preferred materials can have a melting point or about 200°, or 350° F. or higher. Heat weldable products are also preferred.

The material for flashing 10 can be 1-ply, 2-ply or multi-ply, where the layers of different or the same material cover the entire product or a portion of the product. For example, the flashing can be 2-ply along the L-shaped member and flanges and 1-ply at web. Such a configuration will allow for greater flexibility of the flashing at the web, since there is less material to manipulate during the installation process.

FIG. 2 provides another illustration of a flashing embodiment according to the invention. As shown in FIG. 2, flashing 10 comprises an L-shaped member 11 with two legs disposed substantially at a right angle to one another. Two flanges 12 are each disposed along the interior sides of the two legs of the L-shaped member 11. The flanges 12 are connected with one another by way of web 13. In this embodiment, web 13 has more material (i.e., is longer in length) than the web 13 of FIG. 1 and is folded gently to allow for flanges 12 to lie flat against the upper surface of each of the legs of the L-shaped member 11. The flanges 12 can be rotated toward or away from the L-shaped member 11 by any angle D. As with the embodiment shown in FIG. 1, the web 13 here can be the same or a different material than the flanges 12, and/or can be thinner or thicker than flanges 12, but is preferably thinner. In addition or alternatively, a more flexible or elastic material is preferably used for web 13 to allow for stretching of the material around the corner of a structural surface to which it is applied, such as a chimney. The flashing 10 can be applied to the corner of a chimney in the same or a similar manner as described with respect to the flashing embodiment shown and described in FIG. 1.

FIG. 3 provides a view of a flashing 10 similar to that of FIG. 2, with web 13 unfolded and as the flashing may appear as it is removed from the mold after manufacturing. As shown, flashing 10 comprises L-shaped member 11 having two substantially perpendicular legs of generally planar material. The legs of the L-shaped member 11 are integrally connected with another to form a single planar sheet and each is integrally connected with a flange 12, along the length of each interior side of the L-shaped member 11. Web 13 is an extension of flanges 12 and can have a curved (FIG. 3) or triangular (FIG. 2) or square or other shaped edge to allow for folding of the web 13 around a corner surface. With a curved or rounded edge to the web 13, a more aesthetic installation of the flashing is made.

FIGS. 4 and 5 illustrate corner flashing embodiments according to the invention as installed respectively on the corners of a chimney and on a dormer. As shown, the flexible flashing at the webbed portion of the flanges is folded tightly around the corners of the structures to provide for a waterproof seal with or without additional sealant applied. In preferred embodiments, the web portion of the flanges is flexible and/or elastic and can be stretched around the corner structure in a manner to provide substantial surface-to-surface contact between the flanges and the surface of the chimney or dormer.

Any conventional process for manufacturing the flashing can be used and will depend in part on the type of material used, whether plastic or rubber. Typically, the flashing is injection molded but can also be prepared using thermoform processes.

The present invention has been described with reference to particular embodiments having various features. It will be apparent to those skilled in the art that various modifications and variations can be made in the practice of the present invention without departing from the scope or spirit of the invention. One skilled in the art will recognize that these features may be used singularly or in any combination based on the requirements and specifications of a given application or design. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. Where a range of values is provided, each value between the upper and lower limits of that range is also specifically disclosed. The upper and lower limits of these smaller ranges may independently be included or excluded in the range as well. As used in this specification, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. It is intended that the specification and examples be considered as exemplary in nature and that variations that do not depart from the essence of the invention are intended to be within the scope of the invention. Further, the references cited in this disclosure are incorporated by reference herein in their entireties. 

1. Flashing comprising: an L-shaped planar member having an interior L-shaped edge; and two flanges connected with a web and integral with the L-shaped member, disposed along the interior L-shaped edge, and having a continuous upper edge; wherein the interior edge of the L-shaped member is shorter in length than the continuous upper edge of the flanges.
 2. The flashing of claim 1, wherein the L-shaped member and the flanges together comprise a single sheet of plastic or rubber material.
 3. The flashing of claim 2, wherein the material is a thermoplastic polypropylene or EDPM rubber.
 4. The flashing of claim 1, wherein the web provides for flexing of the flanges to any angular position between 0-360° relative to the L-shaped member without imposing stress on the L-shaped member.
 5. The flashing of claim 4, wherein the web provides for flexing of the flanges to any angular position between 45-315° relative to the L-shaped member without imposing stress on the L-shaped member.
 6. The flashing of claim 4, wherein the web provides for flexing of the flanges to an angular position between 0-90° relative to the L-shaped member.
 7. The flashing of claim 2, wherein the flashing comprises one type of material.
 8. The flashing of claim 2, wherein the flashing comprises two types of material and wherein the web is a different material or a different composition of the same material as the L-shaped member and flanges.
 9. The flashing of claim 8, wherein the material of the flashing at the web is more flexible and/or resilient than the material of the flashing at the flanges.
 10. The flashing of claim 2, wherein the flashing comprises a material thickness that is thinner where the flanges connect with the L-shaped member.
 11. The flashing of claim 2, wherein the web is thinner than the flanges. 